Manchester United's season got underway with a shock 3-1 defeat by Crystal Palace as Wilfried Zaha grabbed a late brace for the visitors in the Premier League on Saturday although VAR was once again the centre of attention over a re-taken penalty.

United looked off the pace early on as Andros Townsend put Palace in front after seven minutes, with the home side's campaign starting a week later than initially scheduled due to last season's Europa League commitments running into mid-August.

The defending was poor as Victor Lindelof allowed Jeffrey Schlupp to square the ball for Townsend, whose first goal in 20 league games was aided by slack marking at the far post.

Paul Pogba and Scott McTominay went close for United but they could have been two goals behind at halftime, with a superb David De Gea save keeping out a goal-bound Jordan Ayew strike.

United brought teenager Mason Greenwood on at halftime but their task was made more difficult when the VAR decided that referee Martin Atkinson should consult the pitch-side monitor and he awarded Palace a penalty for handball against Lindelof.

Ayew, whose shot was handled by the defender, had his spot kick briliiantly saved by De Gea. The VAR drama was not done though, with Atkinson informed that the keeper came off his line and the penalty was retaken, with Zaha converting this time.

New signing Donny van de Beek came off the bench to get the home side back in the contest with a goal on his debut after a fortunate ricochet, but former United forward Zaha made sure of a deserved win for Palace with a fine finish late on.

"I feel that it's not a penalty," United manager Ole Gunnar Solskjaer said. "I think the ball comes from so close to Victor, where can he put his hands? The decision to retake it, though, was the right one if you follow the rules."

There is a new directive this season to crack down on keeper encroachment at penalties but, even with VAR being on their side twice in quick succession, Palace were good value for their win, with manager Roy Hodgson full of praise for Zaha.

"I'm very pleased for him and the club," he said. "He's worked hard on getting strikes on target when he gets the chances, and that work is showing now."

Borussia Dortmund forward Erling Haaland scored twice and teenager Giovanni Reyna added another as they cruised past Borussia Moenchengladbach 3-0 in their season opener on Saturday.

The 20-year-old Haaland scored a 54th minute penalty, awarded for a foul on Reyna, and bagged another with a sensationally quick counter-attack and a Jadon Sancho assist as Dortmund utilized their fearsome youthful attacking weapons.

Reyna opened the scoring, after combining perfectly with his fellow 17-year-old Jude Bellingham in the 35th minute. His first league goal made him Reyna the second youngest American to score in the league after Christian Pulisic.

The hosts, playing in front of a crowd limited to 9,300 fans in their 80,000-capacity stadium due to COVID-19 restrictions, also hit the crossbar with a Sancho header.

Champions Bayern Munich launched their title defence with an impressive 8-0 demolition of Schalke 04 on Friday.

(With input from agencies)